1. Field of the Invention
The present invention relates to expansion systems for portable computers and, more specifically, to an apparatus and a method for controlling the power supply of a docking station used with portable computers.
2. Background Art
Recently, portable computers have become a popular alternative to traditional desktop computers in terms of their movability, simplicity, and various functions. Furthermore, various expansion devices have been developed that enable the portable computer to extend its battery life as well as its multimedia capabilities. This development has been spurred by users' desires to overcome the inherent functional limitations, with respect to size, weight, and battery life, of portable computers. Some common expansion, also referred to as peripheral, devices are, for example, external speakers, external CD-ROM drives, external batteries, or AC adapters. These peripherals can often be incorporated into, or interfaced through, a docking station that is specifically designed for a particular type of portable computer.
Usually, a docking station has a special connector, also referred to as a port replicator, that allows the portable computer to interface with peripheral devices, that are attached to the docking station, such as an external display device, a mouse, a keyboard, or a pair of speakers. The port replicator is coupled to an expansion port that is positioned on the rear side of the portable computer, to allow the electrical and mechanical connection of the portable computer with the docking station. With this connection, the peripheral devices and the portable computer can be integrated to enhance the functionality of the portable computer.
Some docking stations have a locking device that allows the portable computer to be secured to the tray of the docking station either manually or using a motor. Furthermore, a diagnostic device may be added to the docking station for issuing a test signal to the interface port and verifying secure electrical connection between the connectors when the system is powered on. Once the test is finished positively, the docking station continues to supply power with the expansion devices installed therein and with the portable computer through the interface port. Some techniques for engaging a portable computer with a docking station are shown, for example, in U.S. Pat. No. 5,377,357 to Nishigaki entitled Connection State Confirmation System and Method for Expansion Unit, U.S. Pat. No. 5,526,493 to Shu entitled Docking Detection and Suspend Circuit for Portable Computer/Expansion Chassis Docking System, U.S. Pat. No. 5,721,836 to Schamberg entitled Method and Apparatus for Sensing and Changing the State of a Computer Before Connecting the Computer to or disconnecting the Computer and From an Expansion Unit, and U.S. Pat. No. 5 5,323,291 to Boyle entitled Portable Computer and Docking Station Having an Electromechanical Docking/Undocking Mechanism and a Plurality of Cooperatively Interacting Failsafe Mechanisms. While many of the techniques for engaging portable computers with docking stations, including those above, concentrate on controlling the state of the portable computer, the contemporary art lacks a docking station power controller that verifies both electrical engagement, a mechanically locked engagement, and the state of the computer power switch, to maintain a power supply.
In the above-mentioned docking station, a problem arises when the portable computer is insecurely coupled to the docking station and the electrical power is still being supplied by the docking station. An additional problem may occur during use, even when there is a secure electrical connection, when the docking station locking device is accidentally released. This will lead to an insecure mechanical connection between the docking station and the portable computer that can lead to sudden separation of the portable computer. An incomplete electrical connection between the portable computer and the docking station may affect electrical safety, or may cause a system fault in either the docking station or the portable computer that can result in electronic damage or data loss.
As such, I believe that the contemporary art may be improved by providing a docking station apparatus and method for controlling the power of the docking station, that verifies a mechanically locked condition between the docking station and the portable computer, that verifies a satisfactory electrical connection between the docking station and the portable computer, and that monitors the state of the power switch of both the monitor and the docking station.